hi!
normally i would simply do the following:
std::vector<Ele ment> vec;
void somefunc() {
Element e;
vec.push_back(e );
}
now Element e is in the vector. thats fine as long as no polymorphic
behaviour is needed.
std::vector<Ele ment &> vec;
void somefunc() {
Derived_from_El ement e;
vec.push_back(e ); //bad idea,.. e is gone after functionscope is left
}
what i want to avoid (if possible) are 2 things:
dynamic allocation of the objects, and having an extracontiner for every
type derived from the basetype to store the elements.
i hope, i made clear what i'm trying to do... so is there a solution (except
for the 2 mentioned above?)
thx, regards,
sev
Jul 22 '05
32  1795 
"tom_usenet " <to********@hot mail.com> wrote in message
news:ne******** *************** *********@4ax.c om... Just curious...What if you don't have (or want) boost? Is there an STL
solution similar to shared_ptr?
boost::shared_p tr has been proposed for standardization as part of the
library technical report. Look out for std::tr1::share d_ptr, coming to
your compiler soon.
Curiosity:
What's the significance of the (namespace?) name 'tr1'?
-Mike
Mike Wahler wrote:
What's the significance of the (namespace?) name 'tr1'?
The C++ standards committee has a Technical Report in the works,
incorporating recommended library extensions. It's known informally as
TR1, and its extensions go in namespace std::tr1.
--
Pete Becker
Dinkumware, Ltd. ( http://www.dinkumware.com)
Mike Wahler wrote:
What's the significance of the (namespace?) name 'tr1'?
The C++ standards committee has a Technical Report in the works,
incorporating recommended library extensions. It's known informally as
TR1, and its extensions go in namespace std::tr1.
--
Pete Becker
Dinkumware, Ltd. ( http://www.dinkumware.com)
Pete Becker wrote: Mike Wahler wrote:
What's the significance of the (namespace?) name 'tr1'?
The C++ standards committee has a Technical Report in the works,
incorporating recommended library extensions. It's known informally as
TR1, and its extensions go in namespace std::tr1.
I don't like the sound of this. Are they going to permanently put these
things in std::tr1::? Why wouldn't they just use std::? If they put it
in std:: later, will they have to also support it in std::tr1:: for
compatibility?
-Kevin
--
My email address is valid, but changes periodically.
To contact me please use the address from a recent posting.
Pete Becker wrote: Mike Wahler wrote:
What's the significance of the (namespace?) name 'tr1'?
The C++ standards committee has a Technical Report in the works,
incorporating recommended library extensions. It's known informally as
TR1, and its extensions go in namespace std::tr1.
I don't like the sound of this. Are they going to permanently put these
things in std::tr1::? Why wouldn't they just use std::? If they put it
in std:: later, will they have to also support it in std::tr1:: for
compatibility?
-Kevin
--
My email address is valid, but changes periodically.
To contact me please use the address from a recent posting.
Kevin Goodsell wrote:
Pete Becker wrote:
Mike Wahler wrote:
What's the significance of the (namespace?) name 'tr1'?
The C++ standards committee has a Technical Report in the works,
incorporating recommended library extensions. It's known informally as
TR1, and its extensions go in namespace std::tr1.
I don't like the sound of this. Are they going to permanently put these
things in std::tr1::?
TR1 puts them in std::tr1. Future TRs and future standards could do
something different.
Why wouldn't they just use std::?
Because they're recommended extensions and not part of the standard.
If they put it
in std:: later, will they have to also support it in std::tr1:: for
compatibility?
Maybe. Maybe the new stuff won't ever go into the standard.
--
Pete Becker
Dinkumware, Ltd. ( http://www.dinkumware.com)
Kevin Goodsell wrote:
Pete Becker wrote:
Mike Wahler wrote:
What's the significance of the (namespace?) name 'tr1'?
The C++ standards committee has a Technical Report in the works,
incorporating recommended library extensions. It's known informally as
TR1, and its extensions go in namespace std::tr1.
I don't like the sound of this. Are they going to permanently put these
things in std::tr1::?
TR1 puts them in std::tr1. Future TRs and future standards could do
something different.
Why wouldn't they just use std::?
Because they're recommended extensions and not part of the standard.
If they put it
in std:: later, will they have to also support it in std::tr1:: for
compatibility?
Maybe. Maybe the new stuff won't ever go into the standard.
--
Pete Becker
Dinkumware, Ltd. ( http://www.dinkumware.com)
Pete Becker wrote: Kevin Goodsell wrote:
Why wouldn't they just use std::?
Because they're recommended extensions and not part of the standard.
OK. I didn't make the connection that a TR is different from a TC, and
was thinking that this /would be/ part of the standard (the comment
"coming to your compiler soon" threw me off). If it's just a
possibility, this makes more sense.
-Kevin
--
My email address is valid, but changes periodically.
To contact me please use the address from a recent posting.
Pete Becker wrote: Kevin Goodsell wrote:
Why wouldn't they just use std::?
Because they're recommended extensions and not part of the standard.
OK. I didn't make the connection that a TR is different from a TC, and
was thinking that this /would be/ part of the standard (the comment
"coming to your compiler soon" threw me off). If it's just a
possibility, this makes more sense.
-Kevin
--
My email address is valid, but changes periodically.
To contact me please use the address from a recent posting.
On 2004-04-06, Severin Ecker <se****@gmx.a t> wrote: std::vector<Ele ment &> vec;
[...]
what i want to avoid (if possible) are 2 things:
dynamic allocation of the objects, and having an extracontiner for every
type derived from the basetype to store the elements.
i hope, i made clear what i'm trying to do... so is there a solution (except
for the 2 mentioned above?)
Severin,
You cannot have a container of references, but you very well can have
a container of pointers, i.e. something like std::vector<Ele ment*>.
Better yet, you can use smart pointers, e.g. boost::shared_p tr<Element>.
In any case, remember that you have to dereference pointers (e.g. using
functors) when you access the data (for example, using standard
algorithms).
You may also want to make your Element class a lightweight proxy that
holds a reference to an actual data stored outside the container.
(Some kind of a Featherweight pattern?)
Hope this helps!
Sergei.
--
Sergei Matusevich,
Brainbench MVP for C++ http://www.brainbench.com This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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